* numeric.c: Fix rdoc for Fixnum#**

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@39062 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
* rational.c (nurat_expt): Deal with special cases for rationals 0, ±1
  [bug #5713] [bug #5715]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@39063 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
* numeric.c (fix_pow): Handle special cases when base is 0, -1 or +1
  [Bug #5713] [Bug #5715]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@39064 b2dd03c8-39d4-4d8f-98ff-823fe69b080e